Drilling tool

Abstract

A drilling tool, in particular for rotary percussion drilling preferably of rock, is proposed, with a drill body preferably equipped with cutting tips toward the drilling side and with an axially arranged bore for receiving an exchangeable center drill. In order to carry out easy mounting and demounting of the center drill, the drilling tool is designed in two parts, the center drill being capable of being introduced into the drilling tool on the clamping side.

What is claimed is: 
     
       1. A drilling tool comprising: a center drill having a center drill shank, a clamping end, and at least one of radially extending projections and widenings on said center drill shank;   a front drill body comprising a drilling side, a clamping side, and an axially arranged bore for receiving said center drill;   a rear clamping end having a clamping shank; and   means for at least one of securing and positioning the center drill provided in the drill body proximal to its clamping end,   wherein the center drill is insertable into said axial bore from the clamping side of said front drill body; the front drill body and the rear clamping end are detachably and directly connectable; and the center drill is detachably connectable to at least one of said front drill body and said rear clamping end by means of radially extended recesses in at least one of said front drill body and said rear clamping end cooperating with the at least one of the radially extending projections and widenings on said center drill shank to effect a positive connection between said center drill and at least one of said front drill body and said rear clamping end.   
     
     
       2. The drilling tool as claimed in claim 1, wherein the radially extended recesses are provided in said front drill body said at least one of the radially extending projections and widenings cooperating with said radially extended recesses to effect a positive connection between said center drill and said front drill body. 
     
     
       3. The drilling tool as claimed in claim 1, wherein the front drill body is connected to the rear clamping end via a screw thread. 
     
     
       4. The drilling tool as claimed in claim 1, wherein the front drill body further comprises a connecting cylinder having an external threaded region and the rear clamping end further comprises a hollow cylinder having an internal threaded region, said hollow cylinder being engagable over said connecting cylinder. 
     
     
       5. The drilling tool as claimed in claim 1, wherein the radial extending recesses comprise at least one of winglike and polygonal recesses, said at least one of the widenings and projections cooperating positively with said at least one of winglike and polygonal recesses to effect a positive connection between said said center drill and at least one of said front drill body and said rear clamping end. 
     
     
       6. The drilling tool as claimed in claim 1, further comprising at least one radially extending transverse slot, into which a crosspin engages positively at the shank end of the center drill. 
     
     
       7. The drilling tool as claimed in claim 1, wherein the center drill is mounted in the drilling tool with axial longitudinal play. 
     
     
       8. The drilling tool as claimed in claim 1, wherein the at least one of the radial projections and widenings on the center drill comprise at least one separate component cooperating with the recesses. 
     
     
       9. The drilling tool as claimed in claim 1, wherein the rear clamping end further comprises an internal thread for receiving at least one of an end external thread of the center drill and positive receiving elements. 
     
     
       10. The drilling tool as claimed in claim 1, wherein a said front drill body is a potlike drill bit. 
     
     
       11. The drilling tool as claimed in claim 1, wherein the front drill body comprises a piercing drill with or without an outer conveying helix, and wherein said rear clamping end can be screwed onto the front drill body at the clamping end of said front drill body. 
     
     
       12. The drilling tool as claimed in claim 8, wherein the separate component is at least one of a pin, ball and ring.